The invention provides an oligodeoxynucleotide containing humanized K-type CpG oligodeoxynucleotide and polydeoxyadenylic acid, wherein polydeoxyadenylic acid is located on the 3 side of the humanized K-type CpG oligodeoxynucleotide. The present invention also provides a complex containing this oligodeoxynucleotide and β-1,3-glucan.